Nut lock



Sept. l, 1931. J, a, DD

NUT LOCK Filed Dec. 19, 1929 A TTORNE Y UNITED STATES PATENT FFICE1H'JAZES B. LADD{ OF ABDIIOBE, I'ENNSYLVANIA; MERRILL A KERCHER EXECIJTOBOF SAID JAMES IB. LAI)ID, DECEASED Application filed December 19, 1929.Serial No. 415,211.

This invention relates to means for looking cooperating threadedelements, such asa nut to a bolt, for the purpose of holding the nutfrom working loose, and refers particularly to means for holding a nutagainst rotation in either directiofiup to a predetermined rotarytorque. r

One of the objects of the inventio'n is to provide an improvedconstruction of the looking means and to have same entirely within thenut with no part exposed to injury from contact with other nuts or thelike,

,- either before or after being put in service.

Another object of-the invention is to provide looking means soconstruted 'as not to be subjected to torsionalvstrains.

A further object is to provide locki ng means which willzbe simple andinexpens1ve and whicl will not require extreme accuracy of parts.

Other objects and advantafies of the con struction Will be seen fromthe; description following and the accompanying drawings,

which illustrate, merely by way of example,

suitable embodiments of the 'invention.

Fi 1 is a plan view of a nut on a bolt with a loc ing pawl. r

Fig. 2 is a part section and part elevatmn of the device shown in.Fig.1.

Fig. 3 is a plan view s owing a modification.

Fig. 4 is a part section and part elevation of the structure shown inFig. 3.

Fig. 5 is a plan view showing a: further modification with the cover 28shown in Fig. 6 removed.

Fig, 6 is a part section and part-levation of thestructure shown in'Fig. 5 with the cover 28 in place.

Fig. 7 is a fragmentary plan view, on an enlarged scale, of anothermodification, and shows in dotted lines an exaggeration of th flexure ofthe pawl.

Fig. 8 is a part section and of the device shown in Fig. 7.

part elevation Fig. 9 is a fragmentary plan view on anenlarged scale ofthe pawl shown in Fig. 1, and shows an exaggeration of the flexure ofthe pin when a rigid pawl is used.

Fig. 10 is a part section and part elevation of the device shown in Fig.9.

Fig. 11 is a plan view on an enlarged scale of the pawl shown in F ig.1, andshows an exaggeration of the flexure Which may occur in both'thepawl and the pin.

Fig..12 isa fragmentary plan view on an enlarged scale of anothermodification.

Fig. 13 is a part section and part elevation of the device shown in Fig.12.

F ig. 14 is a fragmentary plan view on an v enlarged scale of anothermodification.

Fig. 15 is a art section and part elevation of the device s own in F ig.14.

Fig. 16 is a fragmentary plan view on an enlarged scale of anothermodification.

Similar numerals refer to similar parts throughout the several views.

Broadly described, my invention comprises a pawl 22 rigidly connectedwith a pin 23, rotatably se'cured in a nut. The pawl is adapted to moveangularl'y with respect to the axis of the nut and is so located andcnfined that, when the nut is turned onto the bolt the free end of thepawl will be brought into forcible contact with the thread on the boltand will resist the rotation of the nut in the reverse direction up to apredeterrhined torque, and will yield, when the torque is increasedabove the predetermined amount, to be moved angus larly by the reverserotatin of the nut into a position inwhich it will resist the rotationof the nut in the opposite direction,

In general, when the nut 20, with'my locking device, is put on a bolt 21With a righthand thread, the awl 22 will automatically be brought 1nto te position inwhich' it is shown in Fig. 1, by the rotation of the nut inthe direction of the arrow shown, and if the mit is forcibly turned inthe reverse directioin, the pawl will be moved across the radial lineinto the position in which it is shown i n Fig..3. 7 When the pawl is atthe limit of its free an-, guiar movement, in either direction, its freeend 29 extends into the threaded hole or bore of the nut, and when thenut is rotated onto the bolt, said free end is forced beyond said freeangular position and is brought into. forcible contact wit-h the thread'on the bolt.

When the nut has been rotated on the bolt" in the direction of thearrow, in Fig, 1, and the pawl is foreibly in contact with the thread inthe bolt, it is evident that if the nut is rotated in the reversedirection the pa wl must pass a radial position.in"passing" over to theposition sho'wn in permit the awl to he forced by the rotation of thenut e rom the Position shwnin Fig. 1

to the positionsliown in Fig. 3, it is essential that-the pawl must besh0rtened'lengthwise if the pin is rigid, or a portin of the pin 23 larmovement, causes must be moved by flex ure away from the bolt, ifthepawl is ig-id and does. not yield to the compressive strain upon it.This final rizovement,bevond its tree anguflexirre of the pawl when aflexible pawl is used and the pin is confined against movingcircumferentially' relative to the axis of the nut, asshown exaggeratediFig. 7.

When a rigid pawl is us'ed and the upper part of the.pin is free to movecircuinferen-' tially relative to the axis of the nut, this finalmovement causes fiexur of thepin, as siunvn' e xaggerated in Fig. 9.

When a flexible pawl is used and the upper part of thepin is re'eto movecrcuinferen" tially relative to the axis of the nut, this final movementcauses flexure o both the pawl and the pin,

When a rigid pin, such as shown in Fig. 15, is used, a shortening of thepawl is obtained by using a pawl of resilient'nmteral which Will yieldto compress'ion in the direction of its length and will also yield toflexure with respect to itslongitudinal extensin, such as shown in I ig,14.

Particular attention is called to the pawls shown in Figs. 5 and 1 4, assuch paw'ls are of resilient material adapted to yi'eld to compressivestrain in -direction oftheiflength, and also to yield by flexure to thtransverse strain to which'they' will be subjected when their free endsare forced past the"extremes of the free angular motion permitted. It

4 will also be noted that the combined i'esil ience a cylindrical form,

ingle to and fr0m either side" a pin -at a right angle Fig. 3, andtherefore,to*

as shown exaggerated in Fig. 11.:

The pin 23 is fastened se that it cannot work out of its seat, as bymeans such as shown at 26, in Figs. 2, 4, 13 and 15, or at 27 in Figs. 8and 10, or it may be held in by a cover sucn as=28 shown in Figs. 5 and6, which is used when it isdesired that the devicebe fully enclosed:

'1. A device 'forlocking a nut to a bolt or the like corriprising awhich is rigidly attached or integrally formed therewith, said pin beingfree to rotate in a seat formed in the nut with :its'axis'substantiallyparallel with the axis of the nut, the pawl extending from said pin intothe bore of the nut and free to move through a small-'angle to eitherside of the radial position, and means 'coacting with the pawl; to limitsaid free angular movement, said limiting means causin'g the-free end ofthe pawl to forcibly engage the thread on the bolt when the pawl ismoved by rotation of the nut beyond either motion. 2 A

- 2-. Adeviee for looking. a nut "to a bolt or the like:eomprising apawl, to one end of which is rigidly attached or integrally formed alpin ata right angie therewith, said pin being free to rotatein a seatformed in the nut with-its axis substantially 'parallel with the ax-isof the nut, the pawl extending from said pin-into the bere of thenutand'free to move through a small angle to either side of theradialfip0fi'tion,andimeans coacting with the pawhtolimit said freeangular movement, said limitingmeans eausing the free end of the pa'wlto torcibl y engage the thread on the bolt when the pawl is-rnoved byrotation of the nut beyond either limit of its free angular motion, andmeans permitting the free end of the pawl to move toward the main axisof the pin, when thenut is forcibly rotated in-the reverse direction, toturned angularly past a radial position rela tive' to the nut toeugagethe thread on the bolt on the opposite side to 'resist rotation of thenut in the reverse direction.

3.' In a device:asdefined in claim 1, means whereby the free end of thepawl is permitted to move toward the main axis of thepin by flexure.ofthe pin.

' JAMES B. LADD.

limit of its free angular with the thrad on the bolt'ispreferably0f asshown Fig. '7,but may be of atiy form adapted toholdihgth nut againstrotation, either by friction or by bitin into the thread, or both.

pawl, toone end of permit the pawl to be

